Micro-electro-mechanical systems (MEMS) are a class of micron-scale devices, made using semi-conductor processing, that integrate electronic and mechanical device functions on a single integrated circuit. In recent years, MEMS techniques have been developed permitting the uniform fabrication of various microscopic mechanical device structures on a single semi-conductor (e.g. silicon) chip, integrating mechanical functions with electronic signal processing. This integrated fabrication approach offers the potential for substantial reductions in device size and weight, as well as improvements in cost, performance and reliability for MEMS devices.
A variety of MEMS sensors have been fabricated, including seismic activity measurement devices, micro-mirror positioning devices, and accelerometers. For example, MEMS accelerometers are widely used to control air bag deployment in automobiles. MEMS accelerometers use a reference mass (i.e. a proof mass) supported by a movable flexure proximate to a moving body. The motion of the reference mass with respect to the moving body is measured by displacement of the flexure relative to a capacitive detector. The displacement of the flexure may be related to the force applied to the reference mass, and thus to an acceleration of the moving body. Acceleration data may be stored in a memory within the sensor for subsequent processing, or may be transmitted by wire to an external processor. In some applications, accelerometers may be unable to withstand the forces applied to the sensor body without causing damage to the memory within the sensor.